If you are in a Drug PTI program it is in your best interest to continue with your treatment and your hours. That way when you get before the court the court will see that you are serious about your treatment, and about staying with the program. It is always best to see if you can remain in a diversion program if that is possible. You could be facing jail time for contempt of court if you are in the drug PTI program.
If you are on regular PTI and the State has sent your case back to court it may not do you any good to continue with your hours. If you are on regular PTI and you have been given a court date, you have most likely already been kicked out of the program. If this is the case, your case will start over in court and you will be looking at the same charges that you were facing before you entered the PTI program.
In either case it is best to speak with an attorney to see what type of program you are in, and if there is any way to keep you in the PTI program.
I totally agree with Mr. Paulk's answer. Its always best to continue with everything, even if you've blown a drug test or two. The court knows that some people are going to fall back into their old habits and depending upon which judge you get, it may not mean you go to jail. Ultimately, its up to you what happens to you. What they're trying to teach you is to stop doing drugs - for your own good and that of society. If you get that message and stop using drugs, you won't have to worry any longer.